JP3593802B2 - Method of fastening intake manifold in internal combustion engine having two cylinder rows - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for fastening an intake manifold in an internal combustion engine having two cylinder rows, and more particularly to a technique for reducing deformation of a cylinder bore.
[0002]
[Prior art]
Conventionally, when a cylinder head is mounted on a cylinder block of an internal combustion engine, a cylinder bore is deformed by a tightening force (axial force) of a cylinder head bolt (hereinafter, referred to as a “head bolt”) for fastening the cylinder head, and the piston is deformed. There is a problem that the slap noise increases. In order to reduce the deformation of the cylinder bore, for example, as disclosed in JP-A-58-13256 and JP-A-6-346778, the cylinder block is Reinforcement with ribs and bridges was performed.
[0003]
[Problems to be solved by the invention]
However, for example, in an internal combustion engine in which an intake manifold is arranged between left and right banks, such as a V-type engine in which two cylinder rows are arranged in a substantially V-shape, deformation of the cylinder bore is caused by tightening of the head bolt. It has been clarified that not only is it caused by force but also by bolt tightening force when the intake manifold is mounted on the cylinder head.
[0004]
That is, the joint surface between the intake manifold and the cylinder head in the V-type engine is not necessarily parallel in both banks due to variations in machining accuracy and assembly accuracy of the cylinder head and the like. In the fastening method, the cylinder head is moved by the tightening force of a bolt for fastening the intake manifold to the cylinder head, and the joining surfaces are brought into close contact to ensure sealing performance. Therefore, as shown in FIG. 7, when the intake manifold is mounted, the line of action of the force F that the intake manifold 1 presses the cylinder head 2 and the line of action of the frictional force f of the cylinder head 2 (the reaction force of F) are straightforward. A rotational moment (couple) M is generated in the cylinder head 2 not on the line. Then, the cylinder head 2 moves in a state where the rotational moment M is generated, and the outer wall of the cylinder block 3 is pushed outward, so that the cylinder bore is deformed in the thrust direction (see FIG. 8). Further, the tightening force of the intake manifold bolt 4 for fastening the intake manifold 1 to the cylinder head 2 includes a tightening force for a surface pressure for securing the sealing performance of the joint surface, and a force for moving the cylinder head 2. Since the tightening force is excessively added, the deformation of the female screw portion of the bolt fastening hole of the cylinder head 2 is increased, and the deformation of the cylinder bore is increased by this deformation.
[0005]
In order to reduce such deformation of the cylinder bore, it is conceivable to further reinforce the cylinder block with ribs or the like as in the prior art. However, in this case, the weight of the cylinder block increases, and It is necessary to change the design of the cylinder block.
In view of the above-mentioned conventional problems, an object of the present invention is to provide a method of fastening an intake manifold that can reduce deformation of a cylinder bore by merely changing a work order in fastening an intake manifold.
[0006]
[Means for Solving the Problems]
For this reason, the invention according to claim 1 provides a cylinder block having a cylinder formed therein, a cylinder head attached to the cylinder block to form a part of a combustion chamber, and intake air attached to the cylinder head in the cylinder. And a cylinder head bolt for fastening the cylinder head to the cylinder block, and an intake manifold bolt for fastening the intake manifold to the cylinder head. When fastening the intake manifold to the cylinder head, with the cylinder head bolts temporarily tightened , opposing the surface pressure between the cylinder block and the cylinder head, positioning the cylinder head relative to the cylinder block, and , The cylinder head With in clamping force which allows the positioning of the intake manifold against, the intake manifold bolts temporarily tightened, then, after the tightening of the cylinder head bolt, and to perform the tightening of the intake manifold bolts.
[0007]
In the invention described in claim 2, after the intake manifold bolts are temporarily tightened, the tightening of the intake manifold bolts is temporarily loosened.
According to a third aspect of the present invention, the first tightening force for temporarily tightening the cylinder head bolt is set to be smaller than the second tightening force for fully tightening the cylinder head bolt, and the intake manifold bolt is temporarily tightened. The third tightening force was set to be larger than the fourth tightening force for fully tightening the intake manifold bolt.
[0008]
The invention according to claim 4 is configured such that the internal combustion engine is a V-type engine in which two cylinder rows are arranged in a substantially V-shape.
The invention according to claim 5 is configured such that the internal combustion engine is a parallel engine in which two cylinder rows are arranged substantially in parallel.
Here, the parallel engine refers to, for example, an engine type in which two cylinder rows as used in some motorcycles are arranged substantially in parallel, and each cylinder row has an independent crankshaft. Specifically, what is called a square 4 or a tandem twin is applicable.
[0009]
According to a sixth aspect of the present invention, a cylinder block formed with a cylinder, a cylinder head mounted on the cylinder block to form a part of a combustion chamber, and intake air distributed to the cylinder mounted on the cylinder head. in two of the internal combustion engine having cylinder banks configured to include an intake manifold, and when fastening the intake manifold to the cylinder head, and the cylinder block and the cylinder head temporarily fixed state, the cylinder block and the cylinder The intake manifold is temporarily fixed to the cylinder head with a tightening force that enables the positioning of the cylinder head with respect to the cylinder block and the positioning of the intake manifold with respect to the cylinder head against the surface pressure between the cylinder block and the cylinder head. And then fix the cylinder head After, and to perform the fixing of the intake manifold.
[0010]
【The invention's effect】
As described above, according to the first aspect of the present invention, when the cylinder head bolt is temporarily tightened, the positioning of the cylinder head with respect to the cylinder block against the surface pressure between the cylinder block and the cylinder head, In addition, since the intake manifold bolts are temporarily tightened with a tightening force that enables positioning of the intake manifold with respect to the cylinder head, the rotational moment generated in the cylinder head when the intake manifold bolts are temporarily tightened. The cylinder head moves in a state where is reduced, and the joining surface between the intake manifold and the cylinder head becomes a parallel surface. Thereafter, after the cylinder head bolts are fully tightened, the intake manifold bolts are fully tightened, so that unnecessary tightening force can be eliminated and deformation of the cylinder bore can be reduced. Then, as the deformation of the cylinder bore is reduced, the piston slap noise, the oil consumption and the blow-by amount can be reduced.
[0011]
Further, for example, in the case where a cylinder gasket is interposed between the cylinder head and the cylinder block, a gasket that is less expensive than the conventional one is used because the sealing ability between the cylinder head and the cylinder block is improved. It is also possible to reduce the cost.
According to the invention described in claim 2, after the intake manifold bolts are temporarily tightened, the tightening of the intake manifold bolts is once loosened, so that the rotational moment due to the tightening force for moving the cylinder head is reduced, The deformation of the cylinder bore can be further reduced.
[0012]
According to the third aspect of the present invention, since the tightening force for performing the final tightening of the intake manifold bolt is set to be smaller than the tightening force for performing the temporary tightening, the deformation of the female screw portion due to the final tightening is reduced, and the cylinder bore is reduced. Can be further reduced.
[0013]
According to the fourth aspect of the present invention, the internal combustion engine is a V-type engine in which two cylinder rows are arranged in a substantially V-shape. Therefore, the intake manifold arranged between the left and right cylinder heads becomes compact, and Even if the rigidity increases, the deformation of the cylinder bore can be effectively reduced.
According to the fifth aspect of the present invention, since the internal combustion engine is configured as a parallel engine in which two cylinder rows are arranged substantially in parallel, the intake manifold disposed between the cylinder rows is made compact and its rigidity is increased. However, the deformation of the cylinder bore can be effectively reduced.
[0014]
According to the invention as set forth in claim 6, in a state where the cylinder block and the cylinder head are temporarily fixed, the cylinder head is positioned with respect to the cylinder block against the surface pressure between the cylinder block and the cylinder head, and the cylinder is positioned. Since the intake manifold is temporarily fixed to the cylinder head with the tightening force that enables the positioning of the intake manifold with respect to the head, the rotational moment generated in the cylinder head is reduced when the intake manifold is temporarily fixed. In this state, the cylinder head moves, and the joining surface between the intake manifold and the cylinder head becomes a parallel surface. After that, since the intake manifold is fixed after the cylinder head is fixed, unnecessary tightening force can be eliminated, and deformation of the cylinder bore can be reduced.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows a mounting structure of an intake manifold in a general V-type engine. A half skirt type cylinder block 10 and left and right cylinder heads 11 and 12 have a cylinder gasket 13 interposed therebetween. It is fastened by a plurality of head bolts (not shown). Cylinder head mounting portions 15a, 16a formed at the distal ends of the left and right intake ports 15, 16 branching from the intake manifold 14 disposed between the left and right cylinder heads 11, 12; The intake manifold mounting portions 11a and 12a formed respectively are connected to each other by a plurality of intake manifold bolts (hereinafter, referred to as "in manifold bolts") 18 with an intake manifold gasket 17 interposed therebetween.
[0016]
Next, a conventional intake manifold fastening method (hereinafter, referred to as “STD Assy method”) and an intake manifold fastening method according to the present invention (hereinafter, referred to as “in manifold step fastening Assy method”) will be described.
First, an example of the STD Assy method includes the following steps (1 ′) and (2 ′).
(1 ') Connect the cylinder head to the cylinder block. The tightening torque of the head bolt at this time is, for example, 3 kgfm + 60 ° (29.4 Nm + 60 °).
[0017]
(2 ') Connect the intake manifold to the cylinder head. The tightening torque of the intake manifold at this time is, for example, 2.0 ± 0.2 kgfm (19.6 ± 1.96 Nm).
As shown in FIG. 8, as shown in FIG. 8, assuming that the deformation amount in the initial state is 0, the tightening of the head bolt and the in-mani bolt causes the # 3 cylinder and the # 4 cylinder to eventually lose their cylinder bore deformation amounts. The average cylinder bore deformation in the thrust direction is about 31 μm. The cylinder bore deformation increases due to the warm-up of the engine. This is due to the difference in the coefficient of linear expansion between the material of the cylinder block and the cylinder head (the cylinder block is made of cast iron and the cylinder head is made of aluminum alloy). is there.
[0018]
On the other hand, an example of the in-manistep tightening Assy method includes the following steps (1) to (5) (see FIG. 2).
(1) Temporarily fix the cylinder head to the cylinder block. The tightening torque of the head bolt at this time is, for example, 3.0 kgfm (29.4 Nm), 6.0 kgfm (58.8 Nm), and then loosened to 0 kgfm (0 Nm) after performing break-in tightening in two stages. Temporary tightening is performed at 1.0 kgfm (9.8 Nm) [first tightening force] (a to d).
[0019]
(2) Temporarily fix the intake manifold to the cylinder head. The tightening torque of the intake manifold at this time is, for example, 0.4 kgfm (3.92 Nm) and 1.6 kgfm (15.7 Nm). 0.7 ± 0.98 Nm) [Third tightening force] (eg). The final tightening torque of 1.6 ± 0.1 kgfm (15.7 ± 0.98 Nm) in this step corresponds to the surface pressure between the cylinder block and the cylinder head when the cylinder head was temporarily fixed in step (1). In contrast, the tightening torque is set to enable positioning of the cylinder head with respect to the cylinder block and positioning of the intake manifold with respect to the cylinder head.
[0020]
(3) Loosen the tightening torque of the intake manifold bolt to 0 kgfm (0 Nm) (h).
(4) Fix the cylinder head to the cylinder block. The tightening torque of the head bolt at this time is, for example, 3.0 kgfm + 60 ° (29.4 Nm + 60 °) [second tightening force] (i to j).
(5) Fix the intake manifold to the cylinder head. The tightening torque of the intake manifold at this time is, for example, 0.4 kgfm (3.92 Nm), 0.9 kgfm (8.82 Nm), 0.9 ± 0.1 kgfm (8.8 ± 0.98 Nm) [fourth. Final tightening force] (k to m). Here, the final tightening torque of the in-manifold bolt of 0.9 ± 0.1 kgfm (8.8 ± 0.98 Nm) generates a surface pressure that ensures the sealing performance of the joint surface between the intake manifold and the cylinder head. The tightening torque is only 0.9 kgfm (8.82 Nm).
[0021]
As shown in FIG. 3, experimental data of the amount of deformation of the cylinder bore by this fastening method, assuming that the amount of deformation in the initial state is 0, the temporary tightening of the head bolt (step (1)) and the temporary tightening of the inmani bolt (step (1)). 2)), loosening of the manifold bolt (step (3)), final tightening of the head bolt (step (4)) and final tightening of the manifold bolt (step (5)), finally # 3 cylinder and # 4 cylinder The average of the amount of deformation of the cylinder bore in the thrust direction is about 17 μm. The cylinder bore deformation increases with warm-up. The reason for this is the same as in the STD Assy method, and will not be described.
[0022]
Therefore, the cylinder bore deformation amount of the V-type engine was 31 μm by the STD Assy method, but was 17 μm by the in-manistep tightening Assy method, and the deformation amount was reduced by 14 μm.
Next, experimental data showing a difference in operation and effect between the STD Assy method and the in-manistep fastening Assy method will be described.
[0023]
FIG. 4 shows the correlation between the axial force [kgf] of the intake manifold bolt and the moving amount of the cylinder head (which has a strong correlation with the cylinder bore deformation amount) [μm]. It can be seen that they have parallel characteristics. This indicates that the amount of movement of the cylinder head increases as the intake manifold bolt is tightened, indicating that it is not affected by other factors, for example, the order of assembling the engine.
[0024]
FIG. 5 shows the correlation among the axial force [kgf] of the intake manifold bolt, the movement amount [μm] of the cylinder head, the rotation moment [kgfm] generated in the cylinder head, and the cylinder bore deformation amount [μm]. According to the graph, it can be understood that the axial force, the rotational moment and the amount of deformation of the cylinder bore of the intake manifold bolt are reduced although the cylinder head movement amount is increased.
[0025]
The reason why the above-described functions and effects are achieved is that after temporarily fixing the cylinder head to the cylinder block (in a state where the head bolts are temporarily tightened), the surface pressure between the cylinder block and the cylinder head is reduced. Since the intake manifold is temporarily tightened with a tightening torque that enables the positioning of the cylinder head and the positioning of the intake manifold with respect to the cylinder head, the cylinder head is rotated in a state where the rotational moment generated in the cylinder head is reduced. This is because they move and the joining surface between the intake manifold and the cylinder head becomes a parallel surface. Further, unlike the conventional STD Assy method, it is not necessary to tighten the intake manifold bolt with a tightening torque capable of moving the cylinder head by overcoming the surface pressure after the final tightening of the head bolt. The deformation of the female screw portion for the head bolt is reduced, and the deformation of the cylinder bore is reduced. Further, the sealing performance of the cylinder gasket is improved, so that an inexpensive gasket can be used, and the cost can be reduced.
[0026]
In addition, the slap noise of the piston is reduced by reducing the deformation of the cylinder bore, and as shown in FIG. 6, the noise rating of the engine is improved and the engine can be made quieter. Further, it is possible to reduce the oil consumption and the blow-by amount.
Although the present embodiment relates to a V-type engine, for example, a horizontally opposed engine or a parallel engine in which cylinder rows are arranged substantially in parallel (used in some motorcycles and called a square 4 and a tandem twin) A similar effect can be obtained by applying the present invention to another engine type having two cylinder rows.
[Brief description of the drawings]
FIG. 1 is a diagram showing a fastening structure of an intake manifold in a general V-type engine. FIG. 2 is a process diagram showing an example of a fastening method of an intake manifold according to the present invention. FIG. FIG. 4 is a graph showing the correlation between the axial force of the intake manifold fastening bolt and the moving amount of the cylinder head. FIG. 5 is the axial force of the intake manifold fastening bolt, the moving amount of the cylinder head, and the cylinder head. FIG. 6 is a diagram showing a correlation between a rotational moment and a cylinder bore deformation amount generated in the engine. FIG. 6 is a diagram showing a noise score according to a conventional method and an intake manifold fastening method according to the present invention. FIG. 7 is a cause of the deformation of the cylinder bore. FIG. 8 shows cylinder bore deformation due to a conventional intake manifold fastening method, where (a) is a cylinder arrangement diagram, and (b) is an illustration of each process. Diagram showing the cylinder bore deformation amount of the REFERENCE NUMERALS]
10 Cylinder block 11, 12 Cylinder head 14 Intake manifold 18 Intake manifold bolt

Claims (6)

A cylinder block formed with a cylinder, a cylinder head attached to the cylinder block to form a part of a combustion chamber, an intake manifold attached to the cylinder head for distributing intake air into the cylinder, and the cylinder head. An internal combustion engine having two cylinder rows including a cylinder head bolt fastened to a cylinder block and an intake manifold bolt fastening the intake manifold to a cylinder head,
When fastening the intake manifold to the cylinder head, with the cylinder head bolts temporarily tightened , against the surface pressure between the cylinder block and the cylinder head, positioning of the cylinder head with respect to the cylinder block, and The intake manifold bolts are temporarily tightened with a tightening force enabling positioning of the intake manifold with respect to the cylinder head , and then, after the cylinder head bolts are fully tightened, the intake manifold bolts are fully tightened. A method for fastening an intake manifold in an internal combustion engine having two cylinder rows. 2. The method for fastening an intake manifold in an internal combustion engine having two cylinder rows according to claim 1, wherein after temporarily tightening the intake manifold bolt, tightening of the intake manifold bolt is temporarily loosened. The first tightening force for temporarily tightening the cylinder head bolt is set smaller than the second tightening force for completely tightening the cylinder head bolt, and the third tightening force for temporarily tightening the intake manifold bolt is 3. The method of fastening an intake manifold in an internal combustion engine having two cylinder rows according to claim 1, wherein the fourth fastening force is set to be greater than a fourth fastening force for fully fastening the intake manifold bolt. The intake manifold in an internal combustion engine having two cylinder rows according to any one of claims 1 to 3, wherein the internal combustion engine is a V-type engine having two cylinder rows arranged in a substantially V-shape. Fastening method. The fastening of an intake manifold in an internal combustion engine having two cylinder rows according to any one of claims 1 to 3, wherein the internal combustion engine is a parallel engine in which two cylinder rows are arranged substantially in parallel. Method. A cylinder block formed with a cylinder, a cylinder head attached to the cylinder block to form a part of a combustion chamber, and an intake manifold attached to the cylinder head to distribute intake air into the cylinder. Internal combustion engine having two rows of cylinders,
When fastening the intake manifold to the cylinder head, with the cylinder block and the cylinder head temporarily fixed, the cylinder head is positioned relative to the cylinder block against the surface pressure between the cylinder block and the cylinder head. And temporarily fastening the intake manifold to the cylinder head with a tightening force enabling positioning of the intake manifold with respect to the cylinder head, and thereafter, after fixing the cylinder head, fixing the intake manifold. A method for fastening an intake manifold in an internal combustion engine having two cylinder rows.

Images